Large area orientation of block copolymer microdomains in thin films

Abstract

A method and apparatus for orientation of block copolymer microdomains via rapid solidification. Rapid solidification from a solvent may include directional solidification and/or epitaxy to form patterns of microdomains in a film of block copolymer. Microdomains may include various structures formed by components of a block copolymer, such as vertical lamellae, in-plane cylinders, and vertical cylinders, and may depend on film thickness. Orientation of structures in microdomains may be controlled to be approximately uniform, and spatial arrangement of microdomains may be controlled.

1. A method comprising:
 forming a solution including a block copolymer and a solvent for the block copolymer;  
 forming a film using the solution; and  
 separating components of the block copolymer based at least in part on crystallization of the solvent to form microdomains of components of the block copolymer in the film, each microdomain including at least one microstructure formed by at least one component of the block copolymer.  
 
     
     
       2. The method of  claim 1 , wherein the step of separating comprises removing solvent from the film. 
     
     
       3. The method of  claim 2 , wherein the step of removing solvent comprises crystallizing solvent in the film to form at least one crystal structure. 
     
     
       4. The method of  claim 1 , wherein the step of separating components comprises directionally solidifying at least one component of the block copolymer. 
     
     
       5. The method of  claim 1 , wherein the step of separating components comprises crystallizing at least one component of the block copolymer under the influence of a crystal-containing substrate. 
     
     
       6. The method of  claim 5 , wherein the crystallized substrate includes crystallized solvent and the at least one component crystallizes in an alignment with the crystallized solvent. 
     
     
       7. The method of  claim 1 , wherein the step of forming a film comprises forming a film of the solution that is less than a dimension of one period of the block copolymer. 
     
     
       8. The method of  claim 1 , wherein the step of forming a film comprises applying the solution to a contoured substrate so the resulting film has a different thickness at two different areas. 
     
     
       9. The method of  claim 8 , wherein portions of the film in a first area having a first thickness includes microdomains having at least one microstructure formed by a first component of the block copolymer that is different in type or orientation from at least one microstructure formed by the first component of the block copolymer in a second area having a second thickness. 
     
     
       10. The method of  claim 1 , wherein one component of the block copolymer forms a cylindrical structures in microdomains of the one component, the cylindrical structures being substantially vertically aligned with respect to the plane of the film. 
     
     
       11. The method of  claim 1 , wherein one component of the block copolymer forms lamellar structures in microdomains of the one component. 
     
     
       12. The method of  claim 1 , wherein the microdomains including one of the components of the block copolymer are periodically oriented spatially and regularly oriented directionally. 
     
     
       13. The method of  claim 1 , wherein the solvent has a melting point greater than 100° C. and is crystallizable. 
     
     
       14. The method of  claim 1 , wherein the solvent is one of benzoic acid, anthracene, and naphthalene. 
     
     
       15. A method comprising:
 providing a solution of a block copolymer dissolved in a crystallizable solvent;  
 forming a layer of the solution, the layer having regions of different thickness; and  
 phase separating components of a block copolymer in the presence of the crystallizable solvent, the regions of different thickness having different orientations of phase separated components of the block copolymer.  
 
     
     
       16. The method of  claim 15 , wherein the step of phase separating comprises directional phase separating components of the block copolymer. 
     
     
       17. The method of  claim 16 , further comprising:
 forming a solution of the block copolymer and the crystallizable solvent; and  
 wherein the step of directional phase separating comprises inducing directional crystallization of the crystallizable solvent.  
 
     
     
       18. The method of  claim 15 , wherein the step of phase separating components comprises:
 phase separating the block copolymer to form microdomains of components of the block copolymer having an orientation influenced by a crystal structure of the crystallized solvent.  
 
     
     
       19. The method of  claim 15 , wherein the step of forming a layer comprises forming a film of the solution that is less than a dimension of one period of the block copolymer. 
     
     
       20. The method of  claim 15 , wherein the step of forming a layer comprises applying the solution to a contoured substrate. 
     
     
       21. The method of  claim 20 , wherein the contoured surface is topographically patterned and includes a plurality of protrusions and indentations, and wherein the film of solution includes relatively thicker portions in register with indentations and relatively thinner portions in register with protrusions of the surface. 
     
     
       22. The method of  claim 21 , wherein portions of the film in register with indentations of the surface include microdomains of a component of the block copolymer having an orientation different from an orientation of microdomains of the component of the block copolymer in other portions of the film in register with protrusions of the surface. 
     
     
       23. The method of  claim 18 , wherein at least some microdomains include cylindrical structures substantially vertically aligned with respect to a plane of the substrate. 
     
     
       24. A method comprising:
 dissolving a block copolymer in a solvent having a boiling point greater than 50° C.; and  
 phase separating components of the block copolymer at least in part based on crystallization of the solvent which influences the orientation of the phase separated components of the block copolymer.  
 
     
     
       25. The method of  claim 24 , wherein the solvent has a boiling point greater than 70° C. 
     
     
       26. The method of  claim 24 , wherein the solvent has a boiling point greater than 100° C. 
     
     
       27. The method of  claim 24 , wherein the solvent has a boiling point greater than 150° C. 
     
     
       28. The method of  claim 24 , wherein the solvent has a boiling point greater than 200° C. 
     
     
       29. The method of  claim 24 , wherein the solvent has a melting point greater than 100° C. 
     
     
       30. The method of  claim 24 , wherein the solvent has a melting point greater than 150° C. 
     
     
       31. The method of  claim 24 , wherein the solvent has a melting point greater than 200° C. 
     
     
       32. The method of  claim 24 , further comprising inducing crystallization of the solvent to phase separate components of the block copolymer. 
     
     
       33. The method of  claim 24 , wherein the solvent is selected from among benzoic acid, anthracene, and naphthalene. 
     
     
       34. The method of  claim 24 , further comprising applying the block copolymer dissolved in the solvent on a substrate to form a film, and then crystallizing the solvent. 
     
     
       35. A portion of a film including a pattern of nanostructures, comprising:
 components of a block copolymer phase separated by directional solidification caused by crystallization of a solvent to form a pattern including a plurality of microdomains, a first set of microdomains including a first component of the block copolymer forming a first structure type having a first orientation, and a second set of microdomains including a second component of the block copolymer forming a second structure type having a second orientation, wherein the first and second sets of microdomains are periodically oriented spatially and regularly oriented directionally.  
 
     
     
       36. The film of  claim 35 , wherein the block copolymer comprises at least two components A and B. 
     
     
       37. The film of  claim 35 , wherein the block copolymer includes at least three components A, B, and C. 
     
     
       38. The film of  claim 35 , wherein the first structure type includes one of a cylindrical structure, a spherical structure, and a lamellar structure.